= A simple pre-paid example

*Goal:* To implement a simple "prepaid" functionality in the server.

*Time:* 15-25 minutes

*Files:*

- `etc/raddb/mods-available/counter`

Many system administrators wish to implement "prepaid" billing for
their systems. In this exercise, we will configure the server to use a
simple "prepaid" scheme, wherein all users will be permitted to log in
for only one hour a day.

Read `etc/raddb/mods-available/counter` and look for the `counter daily` instance
The documentation for the module consists solely of the comments in
`etc/raddb/mods-available/counter`, so those comments should be read carefully.
Search the rest of the configuration file for references to the `daily` module
and un-comment any references you find.

Add an entry that sets the `Max-Daily-Session`
to have the value 3600 to the top of the file. Start the server, and test it with the `bob.sh`
script. Note that unlike previous responses from the server, this one
contains a `Session-Timeout` attribute with value 3600.

Wait five to ten seconds, and then use the `bob-acct-stop.sh` script to
tell the server that user "bob" has logged off. Observe that the `counter`
module is called and that this module updates the user's login time. Now send the
server another login request (`bob.sh`), and observe that the
"Session-Timeout" attribute has a value less than 3600. The value
should be near 3600. This value depends on the length of time passed
between when the server is started and when the `bob-acct-stop.sh` script is run.

== Questions

1.  How would you configure the server to obtain the daily access limits
from an SQL database?
2.  Why is it useful to enforce time-based restrictions on users, in
addition to enforcing `Simultaneous-Use`?

// Copyright (C) 2021 Network RADIUS SAS.  Licenced under CC-by-NC 4.0.
// This documentation was developed by Network RADIUS SAS.
